Nanomaterials refer to materials of which a single unit is sized (in at least one dimension) between 1 and 1000 nanometers (10−9 meter). Due to the effects resulted by its small size, such as interface effect, quantum size effect and so on, it possess many special properties, and thus has been widely used in many applications.
A nanowire, which is one type of nanomaterials, refers to a wire material of which the radial size is of the order of a nanometer and the longitudinal size is much larger than the radial size. Many different types of nanowires exist. For example, depending on different constitutional materials, there are metallic nanowires (e.g., nanowires composed of Ni, Pt, Au, Ag, etc.), semiconducting nanowires (e.g., nanowires composed of Si, InP, GaN, etc.), and insulating nanowires (e.g., nanowires composed of SiO2, TiO2, etc.). An important usage of conductive nanowires (for example silver nanowires) is used for producing electrodes such as the grids of an array substrate, lead wires and so on. In order to make an electrode made of conductive nanowires having better conductivity, the nanowires should be oriented, that is to say, the nanowires should be distributed substantially along the current transmission direction.
The current methods for forming oriented nanowire materials include masking method, electromagnetic field-aid growing method, dipping method, LB method (Langmuir-Blodgett method), etc. However, all these methods are not perfect and have some defects such as high demands for process conditions, limited application, unsuitability for large-size structures, and inferior orientation of products and so on.